describe('map', function()
  it('produces an error if its parent errors', function()
    local observable = Rx.Observable.fromValue(''):map(function(x) return x() end)
    expect(observable.subscribe).to.fail()
    expect(observable:map().subscribe).to.fail()
  end)

  it('uses the identity function as the callback if none is specified', function()
    local observable = Rx.Observable.fromRange(5):map()
    expect(observable).to.produce(1, 2, 3, 4, 5)
  end)

  it('passes all arguments to the predicate and produces all of its return values', function()
    local callback = spy(function() return 1, 2, 3 end)
    local observable = Rx.Observable.fromTable({3, 2, 1}, ipairs, true):map(callback)
    expect(observable).to.produce({{1, 2, 3}, {1, 2, 3}, {1, 2, 3}})
    expect(callback).to.equal({{3, 1}, {2, 2}, {1, 3}})
  end)
end)